Don Sebastian de Morra was a servant to the Cardinal-Infante don Fernando in Flanders. He returned to Spain in 1643 and entered the service of Prince Baltasar Carlos, dying in October 1649. It is known that the Prince came to like him, as is revealed in the former's will, which left various sumptuary objects to him.

Velasquez plays with the contrast between this dwarf's serious and meditative expression and his physical deformity, which is almost childlike. Thus, the painter offers a reflection on the human condition.

The work reveals Velasquez's capacity to capture the dwarf's seriousness and his profoundly sad expression, emphasizing the painter's feeling of solidarity with the suffering of others.